Procedures for the treatment of cancer generally have been based upon the natural history of tumor spread, and thence, upon operative and non-operative options available to the physician. Operative options generally have looked to the physical identification and surgical resection of tumor. A variety of techniques have been brought to bear in the art with the purpose of aiding the surgeon in detecting and localizing neoplastic tissue as part of this surgical procedure. (“Neoplastic tissue,” for the present purposes, often is referred to as cancerous tissue, though malignant tumor and malignant tumor cells also are found in the terminology of the art. The term “neoplastic tissue” includes all of these.) Typically, large tumor is readily located by the surgeon by visualization at the operating theater, and, in particular, through palpation, i.e., the feel of tumor as opposed to that of normal tissue. To achieve operative success, however, it is necessary for the surgeon to somehow locate “occult” tumor, i.e., tumor which cannot be found by the conventional surgical procedures of sight and feel. Failure to locate and remove such occult tumor generally will result in the continued growth of cancer in the patient, a condition often referred to as “recurrent” cancer.
A much improved method for locating, differentiating, and removing neoplasms uses a radiolabeled antibody injected into the patient. Once injected, such antibodies are known to accumulate in neoplastic tissues at a higher concentration than in normal tissue. A portable radiation detection probe is employed by a surgeon intraoperatively in order to detect sites of radioactivity. Because of the proximity of the detection probe to the labeled antibody, the faint radiation emanating from occult sites becomes detectable, for example, in part because of the inherent application of the approximate inverse square law of radiation propagation. The procedure is now known as radioimmunoguided surgery, or RIGS® (RIGS being a registered trademark of Neoprobe Corporation of Dublin, Ohio).
Similarly, Intraoperative Lymphatic Mapping (ILM) may be utilized to study the effect of neoplastic tissue on a patient's lymphatic system. The lymphatic system provides a vital function in fighting disease; however, this intricate network also creates an ideal pathway for cancer cells to travel and spread. For example, certain solid-tumor cancers such as breast, melanoma, lung, colorectal and head-and-neck cancer frequently spread via the lymphatic system.
The spread of cancer to the patient's lymph nodes is typically determined by examination of the nodes along the likely drainage path by pathology to determine if tumor cells are present. It is not uncommon for a surgeon to remove most of the lymph nodes in the area surrounding a solid tumor. This radical and often unnecessary procedure causes a large number of patients to experience significant complications following surgery.
ILM overcomes many of these drawbacks. In an ILM procedure, a radioactive tracing agent is injected at the site of the primary tumor. Following injection, the tracing agent follows the likely drainage path of the tumor to the initial lymph node or nodes that the tumor may be draining to, referred to as the “sentinel node(s).” A gamma radiation detection device is used to detect the tracing agent. Since the lymph nodes are connected, oncologists believe that if the sentinel nodes show no sign of malignancy, then the downstream nodes in the pathway are likely to be clear of disease, as well. As such, the removal of other nearby lymph nodes would be deemed clinically unnecessary. Therefore, the ability to rapidly locate and biopsy sentinel nodes provides vital information to the physician in determining if the cancer has spread or if it is localized to the site of the primary tumor.
Surgical radiation detection instrumentation is comprised generally of a hand-held probe which is in electrical communication with a control console via a flexible cable. This control console is typically located within the operating room facility but out of the sterile field, while the hand-held probe and forward portions of its associated cable are located within that field. The hand-held radiation detecting probe is relatively small and performs in conjunction with a detector such as a cadmium zinc telluride (CZT) crystal. Details of such instrumentation may be found in commonly owned U.S. Pat. No. 4,782,840, the disclosure of which is expressly incorporated herein by reference.
A drawback of current surgical radiation detection instrumentation is the flexible cable extending between the probe and the control console. If the cable is too short it tends to limit the user's flexibility in positioning the probe. Conversely, if the cable is too long it may become entangled with other instrumentation and equipment. Furthermore, a cable that is not adequately or appropriately sterilized or draped is a potential source of contamination of the operative field.